Pulse Oximeters: How to Measure Oxygen Saturation



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Fingertip Pulse Oximeter – What They Can and Can’t Do

This medical device, called a pulse oximeter, measures the oxygen saturation in a person’s blood. 

They are portable, battery-operated, and suitable for home and travel use. They are beneficial for persons with respiratory or heart problems. It is important to understand what they can and can’t do and how to use one.

What it can do.

Use it to get a continuous reading of your oxygen saturation. Used in home healthcare environments as well as hospitals and clinics. 

They can provide immediate oxygen saturation readings, which makes the pulse oximeter useful in emergency medical situations.

What it can’t do

Blood tests are required to get a complete analysis. They measure only the hemoglobin saturation and are not a complete measure of your respiratory efficiency. 

It doesn’t measure blood flow or the amount of hemoglobin in the blood. The oximeter may give you timely results, but only your doctor can accurately diagnose your medical needs.

How to use it

The oximeter is placed onto any finger (not the thumb) and clamps like a clothespin. With the display pointing up, place the oximeter on the fingertip over the nail. 

Turn the unit on. After about 10 seconds, the display will show your oxygen saturation, usually labeled “SpO2.” 

Your heart rate may include a pulsing light, or a beep indicator will also be displayed. Generally, a SpO2 reading of 95 or above is desired. 

Readings of 95 to 90 are cause for concern and worthy of a call to your doctor. 90 and below, and you need to get attention. 

Everyone is different, with different health issues that affect the outcome. Your doctor can tell you what reading is preferred in your case.

Be careful to move around only a little, or you may get an error reading. A bright light in the area of the oximeter may also affect the reading. Poor blood flow to the finger will affect accuracy.

There are many different pulse oximeters on the market today. It is important to read the owner’s manual to understand the correct and intended use of the oximeter you have.

How they work

Pulse oximeters operate by projecting two wavelengths of light through the top of your nail and skin. Receptors on the underside of your finger receive the light. The difference is measured, and your saturation level is displayed.


Sometimes the “not-knowing” in a medical situation causes additional worry and stress to the patient. 

The ability to know and monitor your oxygen saturation helps to give a person peace of mind.

However, heart and respiratory problems are very serious concerns. Always consult your doctor when you’re unsure.

In conclusion

A pulse oximeter is a handy medical tool that can measure the amount of oxygen in your bloodstream. Offering the convenience of portability, this battery-powered device can be used both at home and while on the go. 

While pulse oximeters can provide quick insight into levels of oxygen saturation, they should not be used as a substitute for a blood test to diagnose any health issues. To get an accurate reading, simply clip it onto any finger (except the thumb) and wait up to 10 seconds for the results. 

Be sure to read the user manual thoroughly so you are familiar with the proper uses for this device. With a pulse oximeter, you can stay reassured by keeping track of your oxygen saturation level—just make sure you consult your doctor if ever in doubt.